---
id: customizing-create-api
title: Customizing createApi
sidebar_label: Customizing createApi
hide_title: true
description: 'RTK Query > Usage > Customizing createApi: adding customized variations'
---

&nbsp;

# Customizing `createApi`

Currently, RTK Query includes two variants of `createApi`:

- `createBaseApi`, which contains only the UI-agnostic Redux logic (the core module)
- `createApi`, which contains both the core and React hooks modules

You can create your own versions of `createApi` by either specifying non-default options for the modules or by adding your own modules.

## Customizing the React-Redux Hooks

If you want the hooks to use different versions of `useSelector`, `useDispatch` and `useStore`, such as if you are using a custom context, you can pass these in at module creation:

```ts
import * as React from 'react'
import {
  createDispatchHook,
  createSelectorHook,
  createStoreHook,
  ReactReduxContextValue,
} from 'react-redux'
import {
  buildCreateApi,
  coreModule,
  reactHooksModule,
} from '@reduxjs/toolkit/query/react'

const MyContext = React.createContext<ReactReduxContextValue | null>(null)
const customCreateApi = buildCreateApi(
  coreModule(),
  reactHooksModule({
    hooks: {
      useDispatch: createDispatchHook(MyContext),
      useSelector: createSelectorHook(MyContext),
      useStore: createStoreHook(MyContext),
    },
  }),
)
```

## Customizing `createSelector` for RTKQ

Both `coreModule` and `reactHooksModule` accept a `createSelector` option which should be a selector creator instance from Reselect or with an equivalent signature.

```ts
import * as React from 'react'
import { createSelectorCreator, lruMemoize } from '@reduxjs/toolkit'
import {
  buildCreateApi,
  coreModule,
  reactHooksModule,
} from '@reduxjs/toolkit/query/react'

const createLruSelector = createSelectorCreator(lruMemoize)

const customCreateApi = buildCreateApi(
  coreModule({ createSelector: createLruSelector }),
  reactHooksModule({ createSelector: createLruSelector }),
)
```

## Creating your own module

If you want to create your own module, you should review [the react-hooks module](https://github.com/reduxjs/redux-toolkit/blob/b74a52935a5840bebca5acdc8e2265e3b6497afa/src/query/react/module.ts) to see what an implementation would look like.

Here is a very stripped down version:

```ts no-transpile
import {
  BaseQueryFn,
  CoreModule,
  EndpointDefinitions,
  Api,
  Module,
  buildCreateApi,
  coreModule,
} from '@reduxjs/toolkit/query'

export const customModuleName = Symbol()
export type CustomModule = typeof customModuleName

declare module '@reduxjs/toolkit/query' {
  export interface ApiModules<
    BaseQuery extends BaseQueryFn,
    Definitions extends EndpointDefinitions,
    ReducerPath extends string,
    TagTypes extends string,
  > {
    [customModuleName]: {
      endpoints: {
        [K in keyof Definitions]: {
          myEndpointProperty: string
        }
      }
    }
  }
}

export const myModule = (): Module<CustomModule> => ({
  name: customModuleName,
  init(api, options, context) {
    // initialize stuff here if you need to

    return {
      injectEndpoint(endpoint, definition) {
        const anyApi = api as any as Api<
          any,
          Record<string, any>,
          string,
          string,
          CustomModule | CoreModule
        >
        anyApi.endpoints[endpoint].myEndpointProperty = 'test'
      },
    }
  },
})

export const myCreateApi = buildCreateApi(coreModule(), myModule())
```
